Deciphering the potential piezoelectricity optimization mechanism in Aurivillius compounds

As a type of high-temperature piezoelectric material, Aurivillius compounds exhibit superior thermal stability and resistivity, yet display a deficiency in piezoelectricity. Currently, despite the successful construction of diverse Aurivillius solid solutions with excellent electro-mechanical properties via composition engineering, this chemical modification necessitates a significant number of trial-and-error experiments, thereby complicating the composition. Herein, based on the typical ferroelectric theory and phase characteristics of Aurivillius compounds, we propose new insight into the piezoelectricity optimization mechanism from the view of relaxation. The introduction of random fields can effectively soften the lattice structure and activate the polarization fluctuation, thereby improving ionic fluctuation, domain dynamics and then piezoelectricity. This finding is believed to provide a systematic framework for optimizing piezoelectric performances, innovating existing piezoelectricity regulation methods and advancing the development of Aurivillius compounds.